The invention relates to a method for checking items belonging to a commissioning order and transported on a conveyor path with respect to product type and number of items by aid of sensing devices connected with a computer.
Moreover, the invention relates to an arrangement for carrying out the method.
At present, in large warehouses, items are arranged manually, semiautomatically or automatically to groups of goods according to commissioning orders and collected in containers. For checking purposes, the containers are guided to weighing devices in the dispatching region so as to compare the net weight of the container contents with the sum of the individual weights of the items. Since in many instances, particularly in the pharmaceutical whole sale business, products weighing less than 10 g are in circulation, checks may often yield incorrect results. A check for the type of product by such a weighing procedure is hardly possible and also difficult, respectively, since many different products have approximately the same weight. Thus, there is a demand for a control which enables a safe check for the type of product and the number of products.
From DE 691 10 852 D2 a method is known for the commissioning of items which are removed from the compartments of shelves by commissioners by hand, are identified by means of a bar code reading device, weighed, and subsequently dropped into an empty or already partially filled container. The containers are transported on a main conveyor path so as to be shifted onto one or several secondary conveyor paths which consist of non-driven rollers; adjacent each secondary conveyor path, a manually displaceable checking device is arranged in which identification and weighing of the items are effected by the commissioner. The containers arriving at the checking device are also identified by means of a bar code reading device, and all the data sensed are monitored by a central computer so as to monitor correspondence of the items commissioned in the containers with the commissioning order; at each checking device, a screen with a keyboard is additionally provided for interactive communication of the commissioner with the central computer. This method thus provides for a check of the items during the commissioning procedure itself, the mode of procedure being comparatively complex and still uncertain.
In EP 572 830 B1 a method of identifying, labelling and targeting of goods at the input of goods and/or at the output of goods in a warehouse is described. By xe2x80x9cgoodsxe2x80x9d, cartons of equal or different sizes containing items are to be understood. These cartons pass a checking station in which a plausibility check takes place, namely whether or not the previously effected identification, weight and volume are in agreement. For identification purposes, a reading device is provided which preferably also consists of six scanners to scan the cartons on all sides or to read the information printed on a label; the read actual data are transmitted to a computer for a comparison with the set data. In this method, however, checking of the items themselves which are contained in the cartons does not take place so that there, too, the disadvantages explained above prevail.
It is thus the object of the invention to provide a method of the initially defined kind as well as an arrangement for carrying out the method by which a precise, in particular automatic, checking of the individual items is carried out while they are being commissioned so as to safely locate faulty groups of goods which do not exactly correspond to a commissioning order.
According to the invention, this object is achieved in the present method in that each item as such is optically or opto-electronically checked while being transported. Due to the fact that the individual items are each separately optically or opto-electronically detected and recognized, this method allows for a safe checking of the items, and advantageously it can be employed not only in new commissioning installations but also in already existing ones so as to completely exclude faulty deliveries, which is of particular importance in case of pharmaceutical products.
With a view to a rapid, automatic and safe checking, it is advantageous if the items are individualized prior to their being checked. Thereby the items can be scanned or xe2x80x9creadxe2x80x9d, respectively, one after the other.
In this connection it is also advantageous if the items are aligned prior to checking; they may thus be brought into a certain longitudinal or transverse orientation which, although preferredxe2x80x94need not necessarily be done since there exist multidirectional electronic scanners, e.g., which can also detect the bar code of non-longitudinally aligned items.
If the items have already been commissioned into containers, according to the invention it is of particular advantage for the checking if the items which have been assembled in a container according to a commissioning order are removed from the container before each of them is checked. Prior to such a check, the items may be individualized and aligned, respectively, as mentioned above. Such a mode of procedure allows groups of items to be put together in the usual manner according to the respective commissioning orders and still to be safely checked automatically as desired for any mistakes which may have occurred during commissioning.
With comparatively poorly identifyable imprints on the items it has also proven advantageous if the items are temporarily stopped while being checked.
Furthermore, it is suitable if the items, in case of a negative result of the check, subsequently are corrected respectively in terms of type and number of products. Subsequently, the item groups initially found to be incorrect can be delivered immediately so as to comply with the commissioning order without having to start commissioning anew.
Moreover, it is advantageous if the items of a negative check result can be removed automatically thus obviating a time-consuming later, in particular manual, search for the faulty items.
For the rational course of commissioning also during checking it has furthermore proven advantageous if the items are transferred into a container after having been checked. In this manner, the items which have yielded a positive checking result can be passed on immediately as a complete group of goods, e.g. for packing and delivery thereof. To reduce the number of containers which are in circulation, it is also suitable if, after checking, the items are transferred into that container which originally contained them.
To effectively shorten the checking procedure, it is particularly advantageous if several items are checked simultaneously.
In an arrangement for carrying out the method, it is provided that the conveyor path comprises a checking station with automatically operating optical or opto-electronical, respectively, sensing devices associated therewith or arranged to follow the former. By this arrangement, minimal time is required as compared with checking carried out by hand, whereby not only the working time as such with the costs associated therewith can be saved, but also commissioning orders can be completed even more rapidlyxe2x80x94and with certainty.
Advantageously it can also be provided that a container-emptying station is associated with the conveyor path and that therebehind an aligning and individualizing station is arranged which is followed by the checking station. By this arrangement, the items can be suitably prepared for the checking procedure proper by being individualized and longitudinally aligned so that misreadings by the sensing devices are excluded. Checking of the individual items themselves on the other hand gives a practically 100% certainty of the check for the correctness of the assembled groups of goods.
A preferred, advantageous embodiment consists in that the checking station comprises a chute formed at least partially of transparent material, at which the optical or opto-electronical sensing devices are arranged transversely to its longitudinal direction. On the chute which is downwardly inclined by e.g. 30xc2x0, the items move past the sensing devices without requiring a separate drive, e.g. a vibration drive, or a separately driven conveyor path therefor whose structure might constitute an optical impediment to the recognition procedure.
A particularly advantageous embodiment provides for the chute to have a V-shaped cross-section. In this case it is suitable if the legs of the chute enclose an angle of 90xc2x0 with each other. In this manner, the items come to lie snugly with two of their longitudinal side faces on the two legs of the V-shaped chute, resulting in ideal conditions for an optical identification.
Advantageously it can also be provided for the checking station to be formed by a path of small rollers. Between adjacent rollers, also the lower side of the items can be checked, while the upper side and the longitudinal side of the items are freely accessible to begin with. If the path of small rollers is arranged to be inclined, this variant does not require an additional drive either.
In terms of complete automation, it is furthermore particularly advantageous if the checking station is followed by a device for automatically removing the items.
In tests, it has proven particularly suitable if as the sensing devices, at least two, preferably four, scanners or video cameras are arranged opposite each other. In this manner, imprints or codes on the items or even their entire appearance can be compared with stored comparative information so as to determine the correctness of the items in a simple and absolutely certain manner. It has proven suitable if four scanners or video cameras are arranged opposite each other in pairs.
If due to poorly identifyable imprints on the items misreadings could occur while they are being moved, it is suitable if a stopping device for the items is arranged in the region of the sensing devices. In this case it is particularly advantageous if the stopping device comprises a solenoid. To stop the items, the solenoid need only be operated for a short time resulting in practically no delay of the passage of the items.
According to a preferred embodiment of the invention it is provided for the aligning and individualizing station to be formed by several, e.g. laterally offset conveyor paths conveying the items at different speeds. This arrangement in practice has yielded very good results, individualizing and aligning of the items being effected in a relatively short period of time. For an alignment of the items while they are being individualized, it is also advantageous if the first conveyor path(s) is (are) provided with directing plates for directing the items to the (respective) consecutive conveyor path. With a view to individualizing, it is suitable if the conveying speeds increase from one respective conveyor path to the next conveyor path.
The invention will be further explained by way of preferred exemplary embodiments to which, however, it shall not be restricted, and with reference to the drawings.